Posted on January 10, 2005 at 10:11Hello Everybody i am new here at the forum and also new to the Microthing so maybe its a stupid message...
I need to set up my ST7FLITE29 to work with PWM Output on 250Khz and a Duty Cycle of 50%. But i cant figure out how to initialise it to do so. I dont understand the Datasheet.
I read some threads here but didnt figure out either.
I calculated the frequency to be ATR value 4080/ 0xFF0
But how do i set the DCR to get 50% and why do i have DRCH and DRCL ????
I am very confused but maybe thats normal at the beginning!
I hope there is someone who can explain whats this about and how to get to the 50%
Below is my code to initialise.
Is it right with the calculation of 4080for 250KHz?? I am running with the internal RC and 8X PLL
//initialising I/O ports
PADR = 0x1C; //setting up dataregister//
PADDR = 0x9F; //setting up datadirection//
PAOR = 0xDF; //setting up dataoptions//
PBDR = 0xFF; //Setting port B dataregisters//
PBDDR = 0x00; //Setting port B Datadirection to input//
PBOR = 0x00; //Setting port B to be floating//
/*******************************************
setting up 12-bit timer for PWM output
***********************************************/
PWMCR = 0x15; //Enabling PWM Output on PWM0, PWM1, PWM2//
ATRH = 0x0F; //Autoreloadtimer High//
ATRL = 0xF0; //Autoreloadtimer Low//
ATCSR |= 0x18; //Set Counter Clk = fCPU//
Thank a lot
Björn
